Parallels Desktop 7 for Mac: How to decompress a hard disk image

by Phil Jones, January 2015

What's this?

You have a hard disk image (.hds) file in Parallels Desktop 7 for Mac,
on which you want to do data recovery. The "DiskDescriptor.xml" file
states that the .hds image file is compressed. Follow these steps to
decompress the image file into a raw disk image, called a Plain disk.

Start Parallels Desktop 7 for Mac.

Click the name of the virtual machine containing the disk image
that you wish to decompress.

Click Virtual Machine menu.

Click Configure.

Click the Hardware tab.

Click Hard Disk 1.

It should say this is an Expanding disk (ie compressed format,
resizable) and its size (64 GB in this example). Ignore the
"Compress..." button; that is to do with reducing unused space inside
the disk image.

Parallels will convert the existing image into a Plain disk
image. The program that does the job is called prl_disk_tool and the
command that is invoked is shown in the Terminal window below. This may
take some time to complete.

Here is the result.

You now have a raw disk image. Example: To see the output, assuming the
default folder locations are used: